As to a conventional cooling structure for an electricity storage device, Japanese Patent Laying-Open No. 10-306722, for example, discloses a battery cooling system for a vehicle that is directed to efficiently cool a battery by the use of air inside a vehicle compartment without impairing comfort inside an air-conditioned vehicle compartment. The battery cooling device disclosed in this document has an exhaust mode in which air after cooling the battery is exhausted through an exhaust duct to the outside of the vehicle, and a circulation mode in which the air is returned into the vehicle compartment through a circulation duct connected to the exhaust duct. In addition, the vehicle is provided with an air-conditioning device for conditioning air inside the vehicle compartment. The air-conditioning device has an interior air circulation mode in which interior air is introduced into an air-conditioning duct, and an exterior air introduction mode in which exterior air is introduced into the air-conditioning duct.
Further, Japanese Patent Laying-Open No. 2004-306726 discloses a battery pack cooling structure that is directed to efficiently cool a battery and an electric instrument attached to the battery. According to this document, cooling air is supplied to a space between battery modules and to a space between a battery unit and a DC-DC converter by the use of a cross-flow fan.
Moreover, Japanese Patent Laying-Open No. 11-180169 discloses an electric part cooling structure that is directed to certainly cool an electric part in an electric car without adversely affecting the reliability and durability of the electric part. According to this document, a battery and an electric part are housed in a battery box. Cooling air introduced into the battery box is adapted to cool the battery and the electric part in sequence.
In the aforementioned battery cooling system for a vehicle disclosed in Japanese Patent Laying-Open No. 10-306722, the exhaust mode or the circulation mode in the cooling device and the interior air circulation mode or the exterior air introduction mode in the air-conditioning device are selected based on the operational status of an air-conditioner, the air-conditioned state inside the vehicle compartment and a battery temperature. In this manner, the battery is cooled while-suppressing decrease in pressure inside the vehicle compartment or increase in air-conditioning load. However, in the case where the temperature of the air to be sent to the exhaust duct is very high, it may become difficult to suppress increase in temperature inside the vehicle compartment and to suppress decrease in inner pressure inside the vehicle compartment at the same time.